Mulan is saying that she can't be herself. In China girls have to act a certain way do they aren't a disgrace to their family. Mulan is saying that she doesn't want to be like that. She's saying that no one knows her true self. It's like she is watching someone that is exactly like her but just isn't her. She may want to make her parents and family proud but she just wants to be herself not someone other people want her to be.